1. Field of the Invention
The invention relates generally to actuating mechanisms for moving various components of a glassware forming machine through their respective operating cycles. More specifically, the invention relates to the components of pusher mechanisms which move glassware containers through a predetermined arcuate path from a dead plate on to a moving conveyor.
2. Description of the Prior Art
Pusher mechanisms for moving glassware articles from a dead plate to a moving conveyor are well known in the prior art. These devices generally include a pneumatic pusher cylinder or head and a rotary actuator means for moving it through a predetermined arcuate path. In operation, each pusher cylinder piston is in a retracted position prior to the deposition of one or more glassware articles on a corresponding dead plate. Extension of the piston rod end by conventional pneumatic means positions fingers at the end of the piston rod near the glassware articles. Movement of the pusher cylinder through an arcuate path is an operating stroke which causes the fingers to contact the ware and move it outwardly through an angle of approximately 90.degree. onto a moving conveyor belt. The piston rod is then retracted and the pusher cylinder returned inwardly on a return stroke in the opposite arcuate direction to complete the cycle.
The arcuate outward velocity of the pusher cylinder is important since it must be slow enough at the start of the cycle so as not to make unstable or break the glassware upon contact with the fingers and subsequently fast enough to match the arcuate glassware velocity to the conveyor velocity.
Electronic pusher mechanisms have been produced where each pusher mechanism may be driven independently of the others according to a predetermined velocity profile by an electric motor controlled by a common control means. In some such prior art units several velocity profiles may be stored in memory and recalled at will. Examples of such prior art electronic pushers are shown in U.S. Pat. Nos. 4,203,752 and 4,313,750.
Each of these prior art electronic pushers requires a relatively large electric motor in driving connection with the pusher cylinder in order to control its arcuate movement in both directions (both inward and outward arcuate strokes). Because the pusher cylinder is a relatively massive component, these electric motors are necessarily large and require high torque, thus, making these prior art electric pusher mechanisms costly and inefficient. Moreover, the return stroke of the pusher cylinder in such prior art electric pushers is constrained by the ability of the electric motor to move the relatively massive cylinder head.
Further prior art is shown in U.S. patent application Ser. No. 520,396 filed Aug. 4, 1983, wherein an actuator has a pneumatic cylinder which is used to linearly advance a splined shaft, which in combination with a splined hub, converts that linear advance to rotary motion. The rotary motion then swings the pusher cylinder through its arcuate path. This splined shaft with its associated splined hub is relatively expensive to fabricate. Furthermore, a backlash may be produced between the hub and the splined shaft when wear occurs, which can contribute to mismovement or inaccurate placement of glassware during operation thereof.
It is an object of this invention, to overcome the disadvantages of the prior art.
It is a further object of the present invention, to provide a motion transmitting mechanism, which converts linear motion to rotary motion, without the drawbacks of the prior art.